Frequently Asked Questions

How long do isolators last?

The normal design life of a bearing isolator is over 50 years. Rubber formulations are stable and durable for long term performance.

What does shear strain mean?

Shear strain is the amount of isolator displacement divided by the rubber height. Design shear strains are up to 250%.

How is the amount of displacement controlled?

The amount of displacement is controlled by damping or stiffness. The addition of damping reduces the displacements and forces in the structure of the building.

How much does it cost?

The cost of seismic isolators varies between 0 & 5% of the cost of the building. In some cases a cost increase of a building is mitigated by a higher resale value.

Can my building be retrofitted?

Yes – it is possible to retrofit a building with seismic isolators. Furthermore a building can remain fully operational during the retrofit procedure.

Does the building need to be isolated at ground level?

No – the building can be isolated at any level.

Will I get cheaper insurance premiums?

There are significant insurance benefits to be achieved by having a building seismically isolated.

Do the isolators need to be replaced after a significant earthquake?

No – there is no need to replace the isolators. The restoring force of the rubber will ensure they return to their original position as the structure re-centres after an earthquake.

How do services such as power cables & water pipes move across the isolation plane in a building?

Utilities must be allowed to move horizontally, they are often fitted with special joints or are made to be flexible.